Not applicable
U.S. Pat. No. 6,591,201
This invention teaches apparatus and methods to generate temperature-controlled and acoustically monitored, transient, ramp, and constant and periodic-steady-state pressure and fluid flow rate conditions from short duration fluid energy pulses to acquire fluid pressure and fluid flow rate test data for fluid control devices in order to create operating points and dynamic fluid flow rate performance curves for a tested fluid control device, such as those that describe the performance of gas-lift valves used in the production of hydrocarbons.
Apparatus and methods to generate high-pressure, high-fluid-flow-rate [HPHFFR] energy pulses to test and evaluate the dynamic operation of fluid control devices and systems are presented in U.S. Pat. No. 6,591,201: Fluid Energy Pulse Test System [FEPTS] by Hyde. U.S. Pat. No. 6,591,201, incorporated herein in its entirety by reference, teaches how to generate short-duration fluid energy pulses and how to use these pulses to identify, record, and evaluate some modes of operation of a fluid control device under test. However, this Patent does not teach how to generate precise transient, ramp, and constant-steady-state fluid pressure and fluid flow rate conditions by short-duration energy pulses so that test data can be used to define the performance of a fluid control device under test. For example, U.S. Pat. No. 6,591,201 does not include transient, ramp, or steady-state performance curves and does not teach how to obtain these curves for tested gas-lift valves. Further, U.S. Pat. No. 6,591,201 does not teach how to control temperature in a test of a temperature-sensitive fluid control device or how to generate periodic-steady-state fluid pressure and fluid flow rate test data. As a result, U.S. Pat. No. 6,591,201 requires improvement by extension and augmentation to demonstrate how to create precise transient, ramp, constant-steady-state, and periodic-steady-state conditions with short-duration energy pulses and how to create transient, ramp and constant steady-state graphs from test data generated by short-duration energy pulses that last seconds or less. Improvements of U.S. Pat. No. 6,591,201 permit transient and ramp fluid pressure and fluid flow rate data acquired by new energy pulse tests to be correlated with, and related to, constant-steady-state data.
The present invention of Fluid Energy Pulse Test Systemxe2x80x94Transient, Ramp, Steady State Tests [FEPTS-TRST] advances the teachings of U.S. Pat. No. 6,591,201 in a number of ways, including apparatus and methods to generate, process, and evaluate transient, ramp, constant-steady-state, and periodic-steady-state test data to establish operating points for fluid control devices, such as gas-lift valves. Operating points are defined by an upstream pressure, a downstream pressure, and a flow rate. The FEPTS-TRST includes: (1) apparatus and methods to regulate and control fluid pressure and fluid flow rate and to create performance curves by defining and subsequently identifying fluid conductance characteristics for a fluid control device under test; (2) apparatus and methods to regulate fluid pressure and fluid flow rate explosively, with pressures ranging from 1480 kPa (200 psig) to 16649 kPa (2400 psig), and fluid flow rates ranging from 2832 SCM/D (100 MSCF/D) to 56,634 SCM/D (2,000 MSCF/D); and with pressure rates varying from 13.890 MegaPa/second to 275.891 MegaPa/second (2,000 to 40,000 psig/second); (3) apparatus and methods to control the temperature of a fluid control device with temperature ranging from 10.0 to 65.55 degrees Celsius (50 to 150 degrees Fahrenheit), or more; and (4) apparatus and methods to acquire sound test data for fluid that is flowing through a fluid control device under test.
The art of regulating fluid pressure and fluid flow rate is documented by patents describing equipment and methods to control fluid pressure and fluid flow rate, including U.S. Pat. No. 4,086,804 to Ruby, J. H. (1978); U.S. Pat. No. 4,777,383 to Waller et. al. (1988); U.S. Pat. No. 4,798,512 to Schmidt et. al. (1989); U.S. Pat. No. 5,020,564 to Thoman et. al. (1991); U.S. Pat. No. 5,142,483 to Basham et. al. (1992); and U.S. Pat. No. 5,357,996 to Ioannides et. al. (1994). While these patents, and others, teach many aspects of regulation, none address equipment and methods to generate and to control fluid pressure and fluid flow rate by explosive HPHFFR energy pulses. Further, references that address the acquisition of sound test data for HPHFFR fluid control devices, such as gas-lift valves, are not widely known. As a result, sound test data and sound-frequency analyses are not available to assist in the evaluation of the dynamic operation of fluid control devices. There appear to be no audio-visual apparatuses and methods in prior art to support the design, testing, maintenance, operation, and evaluation of HPHFFR fluid control devices.
To establish a reference point for the FEPTS-TRST invention, the FEPTS apparatus and methods of U.S. Pat. No. 6,591,201 are discussed below and explained further in FIG. 1 and FIG. 2.
The FEPTS apparatus is fabricated as three connected systems: a compressor system, a valve control system, and a data acquisition system. A compressor system includes compressors operated by remote control to produce high-pressure, high-fluid-flow-rate for driving functions that are generated by the valve control system. Impulse, step, ramp, and frequency driving functions, and combinations thereof, are used to test the dynamic operation of fluid control devices, such as gas-lift valves.
The valve control system activates and deactivates bang-bang and variable-fluid-flow-rate control valves to initiate, control, and end a test. The valve control system includes a large main fluid reservoir; smaller upstream and downstream fluid reservoirs, a test chamber assembly; pipes; electromagnetic and electro-pneumatic bang-bang control valves and variable-fluid-flow-rate control valves; a high current, electric power source for control of the electromagnetic and electro-pneumatic control valves; a low-pressure, fluid power source for control of electro-pneumatic control valves, a valve control computer to generate digital-to-analog signals; and, software to activate the data graph computer, to control test duration, to acquire time-line information about the on/off condition of control valves, and to generate energy pulses. The energy pulses are defined by pulse initiation, delay, duration, amplitude, periodicity, and duty cycle, properties that are associated with impulse, step, ramp, or frequency driving functions.
When initiating a test of a fluid control device, the FEPTS valve control computer activates a data acquisition system. The data acquisition system includes a data graph computer; fluid pressure, fluid temperature, and flow rate transducers; signal conditioners; analog-to-digital converters; and software to acquire temperature, pressure, and flow rate data and to prepare graphs of these data. Analog pressure gauges provide safety-validation of digital data displays. A means to shift control between the data graph computer and the valve control computer before, during, and after a test is also provided
The FEPTS methods acquire test data on a fluid control device installed in a closed-to-the-atmosphere, partly-open-to-the-atmosphere, or open-to-the atmosphere test environment. Each test environment depends upon how fluid conduits in the FEPTS are connected, the type of energy pulse protocol chosen, and how supply fluid and exhaust fluid are stored and controlled.
FEPTS methods include the following procedures: select pipe configurations for a test environment; install a fluid control device; set upstream and downstream initial fluid pressure and fluid flow rate conditions; select test duration, sampling rate, and automatic or manual control; choose an energy pulse test protocol from a computer-based library of test protocols or design a new energy pulse test protocol; start a test; collect test data; end a test; and, construct graphic presentations of test data. Graphs are constructed in time-dependent fluid pressure, fluid flow rate, and fluid-power formats, and in parametric presentations, to illustrate the dynamic characteristics of a tested device, such as a pressure-sensitive gas-lift valve or a safety valve.
In FEPTS tests, HPHFFR energy pulses deplete stored energy explosively. The FEPTS apparatus does not provide adequate means to control and to replace fluid and fluid pressure loss during the generation and expenditure of the energy pulses. As a result, the FEPTS methods do not show how to produce constant-steady-state or periodic-steady-state fluid dynamic data when testing fluid control devices.
World-wide industrial standards for steady state fluid systems incorporate constant-steady-state conditions for the measurement of fluid pressure and fluid flow rate. Industrial concentration upon constant-steady-state conditions is a result of historical precedent and technological development. In practice, measurement of constant-steady-state fluid flow rate is assisted by flow conditioners, entry and exit pipe runs, and by-pass meter runs. A preferred industrial practice is to attenuate transient, alternating, and periodic fluid pressure and fluid flow rate regimes. This practice is costly. This practice limits the development of tools and methods to generate and to measure fluid pressure and fluid flow rate variations. This practice also restricts the design of fluid control equipment and components that function accurately under variable fluid pressure and fluid flow rate conditions.
Conventional flow-loop test methods that characterize the performance of gas-lift valves are described in the references, American Petroleum Institute [API] Recommend Practice for Testing Gas-Lift Valves, December, 1995; and Gas-Lift Valve Performance Testing, API Recommended Practice 11V2, Second Edition, March 2001.
There are two basic types of gas-lift valves: Injection Pressure Operated [IPO] valves, opened by upstream pressure, defined as injection pressure, and Production Pressure Operated [PPO] valves, opened by downstream pressure, defined as production pressure. After each type of valve opens, fluid flows from upstream to downstream through the valve. All IPO and PPO gas-lift valves are sensitive, in varying degrees, to injection pressure and to production pressure and thus are classified as pressure-sensitive fluid control devices. Nitrogen-charged valves are also sensitive to the temperature of the nitrogen gas.
There are two types of conventional steady state flow-loop tests to establish gas-lift valve performance curves: Constant Injection Pressure Test [CIPT] and Constant Production Pressure Test [CPPT]. Injection pressure is associated with upstream valve, or casing pressure. Production pressure is associated with downstream valve, or tubing pressure. In each conventional test, one of the pressures is held constant while the other is changed in steps or ramps to evaluate the sensitivity of a gas-lift valve to one type of pressure change. In both types of tests, fluid flow rate is monitored continuously. Flow-loop tests require long test times and large quantities of fluid energy. Each test generates one set of fluid pressure and fluid flow rate data that are converted into a performance curve. Multiple curves are combined to create a performance graph for a benchmark gas-lift valve to represent all gas-lift valves manufactured to the same specifications. These curves are used to design hydrocarbon-lifting systems. The shortcomings of flow-loop tests of gas-lift valves coupled with the design of hydrocarbon-lifting systems may cause errors as high as 200% in control-variable set points for hydrocarbon-lifting systems.
The high cost in time, equipment, and personnel of conventional flow-loop testing is discussed in detail in the FEPTS U.S. Pat. No. 6,591,201. Conventional flow-loop testing suffers additional disadvantages, including those listed herein below.
(1) The API Recommended Practice is the only method available to establish gas-lift valve performance curves, thereby limiting the ability of valve manufacturers and hydrocarbon production companies to characterize gas-lift valves and other HPHFFR fluid control devices. Except for the FEPTS-TRST invention described herein, there are no other ways to establish constant-steady-state performance curves for gas-lift valves or to acquire constant-steady-state dynamic performance characteristics for other HPHFFR fluid control devices.
(2) Conventional flow-loop testing demands large and costly facilities, and requires a minimum of three operators to conduct tests. As a result, only a few performance curves are acquired during a test. If a fluid flow rate characterization is needed, but was not acquired during a test, the data must be interpolated.
(3) In conventional flow-loop testing to establish performance curves, one trace is acquired for a given set of test parameters. When a test is initiated, the test continues until completed or aborted. There are no economical ways to test repeatedly one or more operating points of a fluid control device, to evaluate a small region of the performance graph, or to investigate and characterize device nonlinearities and/or anomalies.
(4) Conventional flow-loop testing technology for gas-lift valves does not provide a measure of accuracy and precision for the data acquired when characterizing the performance of a valve. It is too costly to repeat tests a number of times to determine the accuracy and reproducibility of the data.
(5) Conventional flow-loop tests of gas-lift valves are conducted without addressing the sensitivity of test parameters. If a known error is made in setting a test parameter, the test is continued with the error uncorrected. To correct the error, a complete retest is required to reach the operating point at which the error occurred. Re-testing significantly increases testing costs.
(6) The conventional standard for evaluating the steady-state performance of a gas-lift valve requires either the CIPT or the CPPT to determine how a valve responds to either upstream or downstream pressure changes. Conventional flow-loop testing is not structured to establish a way to combine the principles of, or the results from, the CIPT and the CPPT.
(7) Except in specialized systems, such as fluidized-bed reactors, fuel injection systems, and packaging systems, there are limited applications of periodic fluid pressure and fluid flow rate. In most industrial applications, unwanted periodic fluid pressure is removed by surge tanks. The absence of efficient and cost-effective periodic, fluid pressure and fluid flow rate energy sources limits design, fabrication, and application of devices utilizing periodic fluid pressure and fluid flow rate.
(8) Conventional flow-loop tests of fluid control devices, such as gas-lift valves, are conducted at ambient temperatures and do not provide a precise way to evaluate performance at industry-standard temperatures, such as 15.55 degrees Celsius (60 degrees Fahrenheit), or at other temperatures that may reach 65.55 degrees Celsius (150 degrees Fahrenheit) or more. In a flow-loop test, the temperature of the flowing fluid is assumed to represent the temperature of nitrogen in a nitrogen-charged gas-lift valve, which assumption can be shown to cause sizeable errors. Flow-loop test fluid pressures and fluid flow rates must be corrected for temperature dependence by table-lookup, in order to back-reference data to the industry standard for a tested device.
With an objective to generate constant-steady-state conditions from short-duration energy pulses, regulating fluid pressure and fluid flow rate requires special attention. Conventional regulators need a finite time to sense change, transmit information, activate control, and recycle. Several cycles may be required to reach a regulated set point. This process is defined by first-order behavior so that as fluid pressure and fluid flow rate approach a desired set point, a proportionally longer time is needed to reach the set point. In energy pulse generation, the response time of a regulator becomes a critical parameter. Conventional regulators, in conventional applications, do not provide adequate fluid pressure and fluid flow rate recovery. Additional problems in restoring explosive fluid pressure and fluid flow rate loss involve the compressibility of the fluid and the quantity of fluid needed for processing. The compressibility of air prevents achieving a state of thermodynamic equilibrium with small quantities of air in short times at high fluid pressures and high fluid flow rates. The properties of air dictate that air temperature increases with compression and decreases with expansion. A constant-steady-state condition assumes thermal equilibrium at a given fluid pressure and fluid flow rate. True thermal equilibrium cannot always be achieved with energy pulses at high fluid pressures and high fluid flow rates when pulse duration is very short. However, when explosive regulation is tempered by the operation of a pressure-sensitive device, a xe2x80x9ccompressible equilibriumxe2x80x9d can be achieved. Thermal conditions reach a near constant state. For constant-steady-state paths, a compressible equilibrium can be extended by lengthening an energy pulse. As a pulse lengthens, it assumes the character of constant-steady-state conditions and long-pulse test results can be compared to short-pulse test results to establish error criteria for fluid pressure and fluid flow rate test data.
There is a general lack of information about testing and measuring sound properties in HPHFFR systems, especially systems that use explosive energy pulses. There is limited technical information about the intensity, duration, frequency range, and robustness of sound waves in HPHFFR systems. Sonic time traces and spectral properties do not seem to have been used for evaluating various dynamic operating characteristics of HPHFFR fluid control devices. For example, information that explains how to measure sound frequencies and how to correlate sound data with conventional fluid pressure and fluid flow rate measurements for HPHFFR fluid devices and systems is not widely known.
In accordance with the principles of the presently disclosed invention Fluid Energy Pulse Test Systemxe2x80x94Transient, Ramp, Steady State Tests [FEPTS-TRST], the FEPTS-TRST invention uses HPHFFR energy pulses to generate transient, ramp, constant-steady-state, or periodic-steady-state conditions by appropriate regulation and control of fluid pressure and fluid flow rate in tests of fluid control devices and systems. When the FEPTS-TRST invention generates an explosive change of energy, measured fluid pressures and fluid flow rates follow transient, ramp, constant-steady-state, or periodic-steady-state paths.
To improve the FEPTS apparatus and methods that characterize the performance of fluid control devices, U.S. Pat. No. 6,591,201 is augmented and extended by sets of components that are integrated with FEPTS equipment, by new methods to control these components, and by new methods to interpret acquired test data. Improvements to FEPTS equipment include a directional switch array; an explosive regulation assembly; a temperature control assembly; a test chamber assembly; and an audio assembly. New methods include procedures to establish transient, ramp, constant-steady-state, and periodic-steady-state operating points to create performance curves for a tested device; to construct transverse lines that establish measures of fluid conductivity of a tested device; to construct regulator lines that exhibit multiple levels of fluid conductivity of the tested device; and procedures to correlate dynamic performance characteristics with sound signatures of a tested device.
A plurality of control signals that were dedicated in the FEPTS to specific control valves and set valves, but which control valves and set valves are not required for a given test protocol, are directed to integrated control valves, set valves, and regulators. These directed control signals allow the integrated control of FEPTS-TRST components. The FEPTS-TRST teaches how to direct and to adapt these control signals to integrated components for testing, thus providing a significantly greater range of testing capability for fluid control devices.
FEPTS-TRST tests are conducted in three to five seconds with energy pulses in a range of 0.020 seconds to four seconds. Longer test times and pulse durations may be required, depending upon the test requirements and the performance of a tested fluid control device. FEPTS-TRST regulation of fluid pressure and fluid flow rate is based upon the fluid pressure and fluid flow rate demands of a test protocol. Regulation is accomplished either by fluid pressure and fluid flow rate regulators under bang-bang control or by pre-set set valves under bang-bang control, either of which meter, under a planned fluid pressure profile, a quantity of fluid to flow into upstream or downstream fluid reservoirs from a high-pressure reservoir. Explosive regulation of fluid pressure and fluid flow rate uses simultaneous control signals to activate bang-bang control valves upstream and downstream of a fluid control device under test. Bang-bang control generates explosive, high-pressure fluid pulses to enter fluid reservoirs, pass through a fluid control device under test, and exhaust to a downstream reservoir or to the atmosphere. Sound waves generated by flowing fluid are measured by sound transducer means upstream and downstream of a fluid control device under test.
In the FEPTS-TRST apparatus, transient fluid pressure and fluid flow rate test data are generated explosively, without regulation, using a negative energy pulse that is created by bang-bang control to activate only a downstream regulator. Ramp and constant-steady-state fluid pressure and fluid flow rate test data are generated explosively, with regulation, using a positive energy pulse that is created by bang-bang control to activate an upstream regulator and using a negative energy pulse that is created by bang-bang control to activate simultaneously a downstream regulator. Periodic-steady-state fluid pressure and fluid flow rate test data are generated explosively, with regulation, using either a series of positive energy pulses created by bang-bang control of an upstream regulator while downstream set valve conditions are held constant, or by variable control of a downstream regulator or set valve while upstream regulator conditions are held constant.
FEPTS-TRST upstream pressure, downstream pressure, and flow rate test data acquired at specific times establish operating points that are used to create performance curves and transverse lines for a fluid control device under test. Performance curves provide information about how a tested fluid control device functions at specific operating points. Transverse lines provide new information about how a fluid control device functions under conditions of constant fluid conductivity, while also providing information about how the device functions at specific operating points. Transverse lines are created as a result of a constant setting of a downstream set valve regulator during energy pulse tests. These lines focus to the origin of coordinates of a graph of fluid flow rate with respect to fluid pressure and cross, diagonally, the set of performance curves constructed from fluid control device operating points. In addition to providing new information about fluid conductivity associated with a fluid control device under test, transverse lines also establish a continuum of upstream pressure, downstream pressure, and flow rate operating points. Performance curves and transverse lines are created for transient, ramp, and constant-steady-state fluid pressure and fluid flow rate conditions. These performance curves and transverse lines are identified and distinguished appropriately as transient performance curves and transient transverse lines, ramp performance curves and ramp transverse lines, and constant-steady-state performance curves and constant-steady-state transverse lines. Sound waves generated by flowing fluid, with or without regulation, reflect the characteristics of transient, ramp, constant-steady-state, and periodic-steady-state operation of a fluid control device under test. Sound test data correlate with both time and amplitude characteristics of fluid pressure and fluid flow rate test data, while providing sound frequency separation and frequency spectral properties. Sound frequency information is analyzed by Digital Signal Processing methods.
FEPTS-TRST periodic-steady-state test data provide new information about hidden and difficult to measure dynamic operating properties of fluid control devices including reaction time, pressure delay, and fluid flow rate delay, all of which may be frequency dependent.
Explosive energy is regulated in the FEPTS-TRST apparatus by Method A, a bang-bang, pre-set variable regulation with pressure feedback; or by Method B, a bang-bang, pre-set constant regulation without pressure feedback.
Method A is a forgiving fluid pressure and fluid flow rate regulating process that requires an explosive regulation assembly comprising a regulator in series with a bang-bang control valve and a pre-set pressure-regulating set point. The regulator utilizes pressure feedback from a target-regulated fluid reservoir. Pressure feedback, coupled with bang-bang control of regulation of a target reservoir from a high-pressure reservoir, generates explosive regulation of fluid pressure and fluid flow rate to the target reservoir. A bang-bang actuator causes the regulator orifice opening to increase or decrease rapidly when regulation is initiated. With this bang-bang control, the regulator over-corrects, then corrects for an increase or decrease in feedback pressure, thereby permitting regulation either from very high initial pressures to a lower regulated set point or from very low initial pressures to a higher regulated set point. An increase in the speed of regulation occurs when the initial pressure within the target reservoir is at, or close to, the desired regulated set point for the target reservoir. This method is forgiving. If the initial condition of the target reservoir is above or below the set point of the explosive regulation assembly, the set-point regulation of the target reservoir is still achieved quickly. The effect of regulating fluid pressure and fluid flow rate by an explosive regulation assembly is to reduce the time constant of regulation.
Method B is an unforgiving fluid pressure and fluid flow rate regulating process that requires an explosive regulation assembly comprising a set valve in series with a bang-bang control valve and a pre-set pressure-regulating set point. This method does not utilize pressure feedback from a target-regulated pressure chamber. Regulation is controlled by the bang-bang actuator, which permits more or less fluid to be restored to the target reservoir. The amount of energy restored depends upon the upstream drive pressure and the set-valve orifice open-state. The method is unforgiving because, once a setting is fixed in the explosive regulation assembly, no change in regulation parameters are generated by the bang-bang actuator or the set-valve.
Accordingly, with the invention of FEPTS-TRST, there are provided:
(1) apparatus and method to conduct constant-steady-state tests of fluid control devices or fluid systems using HPHFFR energy pulses of short duration, wherein constant-steady-state fluid pressures and fluid flow rate are achieved and maintained for short periods of time by an explosive burst of controlled fluid energy that regulates fluid pressures and fluid flow rate;
(2) apparatus and method to conduct periodic-steady-state tests of fluid control devices or fluid systems using HHFFR energy pulses of short duration, wherein periodic-steady-state fluid pressures and fluid flow rate are achieved and maintained for short periods of time by periodic explosive bursts of controlled fluid energy that regulate periodic fluid pressures and fluid flow rate;
(3) apparatus and method to create transient performance curves and transient transverse lines for a fluid control device under test;
(4) apparatus and method to create ramp performance curves and ramp transverse lines for a fluid control device under test;
(5) apparatus and method to create constant-steady-state performance curves and constant-steady-state transverse lines for a fluid control device under test;
(6) apparatus and method to create transient, ramp, or constant-steady-state operating points with a downstream back pressure regulator;
(7) apparatus and method to direct control signals for control valves and set valves to integrated control valves, set valves, and regulators;
(8) apparatus and method to hold the temperature of a fluid control device under test constant at a temperature in the range from 10.0 to 65.55 degrees Celsius (50 to 150 degrees Fahrenheit) or more;
(9) apparatus and method for a test chamber assembly, comprising an upper retaining plate, an upper test chamber unit, a second-device heat exchanger, a first-device heat exchanger, a lower test chamber unit, a lower retaining plate, xe2x80x9cOxe2x80x9d rings, supporting members, and temperature and pressure transducers;
(10) apparatus and method for an explosive regulation assembly comprising a regulator and a bang-bang control valve to regulate fluid pressure and fluid flow rate from an upstream high-pressure reservoir to a downstream target reservoir in order to generate explosive energy pulses for ramp, constant-steady-state, or periodic-steady-state fluid pressure and fluid flow rate conditions;
(11) apparatus and method to improve the accuracy in testing gas-lift valves so that test data error levels are nominally xc2x12 percent or less for orifice flow regions and xc2x115 percent or less for throttling flow regions, or less, which nominal errors are significantly less than industry accepted standard error levels of xc2x15 percent for orifice flow regions and xc2x130 percent for throttling flow regions;
(12) apparatus and methods to record and play sound frequency data derived from a fluid flowing through a fluid control device under test with data acquired by HPHFFR microphones upstream and downstream, of said device, that are part of an audio assembly;
(13) a method to create constant-steady-state performance curves from constant-steady-state operating points without constructing constant-steady-state transverse lines;
(14) a method to test and retest transient, ramp, constant-steady-state, or periodic-steady-state fluid pressure and fluid flow rate operating points of a fluid control device in specific regions of a performance graph in order to establish accuracy, precision, sensitivity, and reproducibility of test data;
(15) a method to construct a single transverse line that is sufficient to demonstrate that a tested device is operating according to design specifications; and,
(16) a method to correlate upstream and downstream sound information acquired by HPHFFR microphones with fluid pressure and fluid flow rate data for a fluid control device under test.
In the FEPTS-TRST apparatus and methods, operating points and transverse lines for a fluid control device installed in a test chamber assembly are acquired in at least four ways.
(1) Downstream pressure of a fluid control device is controlled by a set valve. Upstream pressure and fluid flow rate are not regulated. A transient decrease in upstream pressure and fluid flow rate is generated by exhausting downstream fluid. Transient operating points are produced at each downstream set valve open state. Transient operating points establish a transient transverse line for each downstream set valve open state.
(2) Downstream pressure of a fluid control device is controlled by a set valve. Upstream pressure and fluid flow rate are regulated for either increasing or decreasing linear fluid pressure and fluid flow rate. For either regulation protocol, ramp operating points are produced at each downstream set-valve open state. Ramp operating points establish a ramp transverse line for each downstream set-valve open state.
(3) Downstream pressure of the fluid control device is controlled by a set valve. Upstream pressure and fluid flow rate are regulated at a constant-steady-state condition. One constant-steady-state operating point is produced at each downstream set-valve open state for each upstream constant-steady-state condition. Multiple constant-steady-state operating points that are produced by a constant downstream set-valve open state establish a constant-steady-state transverse line.
(4) Downstream pressure of a fluid control device is controlled by a back pressure regulator. Upstream pressure and fluid flow rate may or may not be regulated. Depending upon the type of upstream regulation, at least one transient, ramp, or constant-steady-state operating point is produced for each back pressure setting. A constant back pressure regulator setting and multiple upstream regulator settings produce multiple operating points. These operating points establish a regulator line that is displaced from the origin.
The identification of gas-lift valve operating points permits re-testing fluid pressure and fluid flow rate performance to evaluate closely the effect of variations in upstream and downstream pressures. The slope of a transverse line has dimensions of fluid flow rate with respect to downstream fluid control device pressure SCM/D/kPa (MSCF/D/pound downstream device pressure), which is a dimension of fluid conductivity. Fluid conductivity and operating points are not available with conventional flow-loop test systems. The FEPTS-TRST invention produces operating points, transverse lines, and measures of conductivity that can be evaluated repeatedly at any location on a performance graph of fluid pressure and fluid flow rate. Fluid conductance is a measure of the sensitivity of pressure-sensitive fluid control devices to simultaneous changes in upstream pressure, downstream pressure, and fluid flow rate. This FEPTS-TRST new result couples upstream and downstream test data, which cannot be coupled by conventional industry standard CIPT and CPPT flow-loop tests. The transverse lines constructed from FEPTS-TRST test data represent a continuum of flow rates for a continuum of downstream pressure control settings at a continuum of upstream device pressures. The slope of a transverse line shows how a pressure-sensitive fluid control device responds to changes in upstream pressure and downstream pressure when the conductance of fluid flow is constant. For example, on a FEPTS-TRST graph, conductance may vary from 29.41 SCM/D/MegaPa (0.1124 MSCF/D/#) with 6307 kPa (900 psig) upstream device pressure, 6238 kPa (890 psig) downstream pressure, and 2.817 MSCM/D (100 MSCF/D) fluid flow rate, to 842.3 SCM/D/MegaPa (3.219 MSCF/D/#) with 6307 kPa (900 psig) upstream device pressure, 1205 kPa (160 psig) downstream pressure, and 14.583 MSCM/D (515 MSCF/D) fluid flow rate. These conductances also exist at 5962 kPa (850 psig) upstream device pressure, 5927 kPa (845 psig) downstream pressure, and 2.690 SCM/D (95 MSCF/D) fluid flow rate, and at 5962 kPa (850 psig) upstream device pressure, 929 kPa (120 psig) downstream pressure, and 10.9 MSCM/D (385 MSCF/D) fluid flow rate, respectively. The slope of a transient, ramp, or constant-steady-state transverse line, and therefore the fluid conductivity of a fluid control device under evaluation at a series of related operating points, can be determined by one point within the fluid control device operating region. Each transient, ramp, or constant-steady-state transverse line is focused on the origin of coordinates.
Under periodic-steady-state testing conditions, the amplitude, frequency, and duty cycle associated with energy pulses generated by the FEPTS-TRST invention can be increased or decreased, depending upon reservoir reserve capacity and the demands of a test protocol. This control of energy pulses produces a wide range of fluid driving functions that can be used to test a fluid control device. For example, periodic-steady-state energy pulses can be generated for periods that may last a fraction of a second or that may last several seconds or minutes.
Periodic-steady-state fluid pressure and fluid flow rate operating conditions are generated in two ways.
(1) Upstream device reservoir fluid pressure and fluid flow rate are regulated explosively at a specific set point. Downstream fluid pressure and fluid flow rate are controlled at a specific set-valve open state. Periodicity in regulation is achieved by either bang-bang operation of an upstream control valve at a specific upstream regulating set point or by analog control of the regulator set point. Bang-bang control is a preferred embodiment. Upstream reservoir periodic fluid pressure and fluid flow rate are controlled by adjusting the bang-bang duty cycle, which permits the target reservoir to lose fluid pressure and fluid and to recharge with periodic consistency. Various pulsating steady-state conditions can be generated by shifting the set point of the upstream regulator
(2) Upstream device reservoir fluid pressure and fluid flow rate are regulated explosively at a specific set point. Downstream fluid pressure and fluid flow rate are controlled by adjusting a downstream set-valve open state. The downstream set point can be changed to reflect a level of fluid conductivity. Shifting the downstream set point is accomplished by either analog control or bang-bang control with variable duty cycle. Various pulsating steady state conditions are generated by shifting the set point of a downstream set valve.
Sounds generated by fluid flowing through a fluid control device are recorded by one microphone with a dedicated channel placed upstream of the device under test and a second microphone with a dedicated channel placed downstream of the device under test. Dual channel sound data show that upstream sound data correlate well with upstream and downstream fluid pressure and flow rate test data while downstream sound data do not have a similar property.
Accordingly, objects and advantages of the FEPTS-TRST invention are:
(1) to provide apparatus and methods to generate, from short duration energy pulses, fluid pressure and fluid flow rate test data that describe transient, ramp, constant-steady-state, or periodic-steady-state fluid pressure and fluid flow rate profiles for pressure-sensitive fluid control devices;
(2) to provide apparatus and methods to improve the FEPTS apparatus and methods taught by U.S. Pat. No. 6,591,201, in order to generate transient, ramp, constant-steady-state, and periodic-steady-state fluid pressure and fluid flow rate test data for pressure-sensitive fluid control devices from short duration energy pulses.
(3) to provide apparatus and methods to direct computer-generated signals to a plurality of integrated control valves, set valves, and regulators in order to extend the capabilities of the FEPTS apparatus;
(4) to provide apparatus and methods for an explosive fluid pressure regulation assembly for HPHFFR energy pulse generation so that explosive fluid pressure and fluid loss from fluid reservoirs can be restored;
(5) to provide test methods to generate data for evaluating different operating regions of a fluid control device in order to determine the sensitivity of the device to changes in fluid pressure;
(6) to establish transient performance curves as useful tools for describing the dynamic operation of pressure sensitive fluid control devices;
(7) to provide a method to correlate HPHFFR transient and ramp performance curves to constant-steady-state performance curves for a given fluid control device,
(8) to show how the dual sensitivities of a pressure-sensitive device to upstream and downstream fluid pressure can be captured on a performance graph;
(9) to show that transverse performance lines can be constructed by identifying a single operating point on a graph of test data;
(10) to provide apparatus and methods that demonstrate procedures to test and retest HPHFFR fluid control devices with a large reduction in time, facilities, personnel, and cost compared to conventional flow-loop testing;
(11) to provide apparatus and methods to control the temperature of a temperature sensitive fluid control device when the device is subjected to transient, ramp, constant-steady-state, and periodic-steady-state fluid pressure and fluid flow rate test protocols.
(12) to provide apparatus and method to generate sound data for a fluid control device under test, which sound data can be correlated with fluid pressure and fluid flow rate test data that are measured by fluid pressure and fluid flow rate transducers.
(13) to provide apparatus and methods to replace large, expensive, and expensive to operate, conventional flow-loop test facilities that currently produce a limited evaluation of the dynamic operation of a fluid control devices under test, by providing test data that are difficult to analyze, lower in accuracy, lower in precision, higher in error, lower in scientific value, and time consuming to generate in comparison to the FEPTS-TRST apparatus and methods.
Further objects and advantages will become apparent from consideration of the following descriptions and drawings.